Tested a Chevy 454 (Old LS6 engine with blower pistons and Dart heads) on the dyno last week. First time I've helped test a blower motor. Engine pulled a rocker arm stud out of the head on the first pull so that took a bunch of work to fix. Took a few days to repair the head and then we were able to get some good pulls on it. This is a boat motor so it was built really conservative. I think the compression ratio was 8.5 and it had 32 degrees of timing and a small flat tappet cam with 0.500 lift. It still made 700 hp and a ton of noise. I think it was the loudest engine we've ever ran on the dyno. Just starts to shriek once you get over 5000 rpm. Not so sure I'd like that noise in a car. The owner says he doesn't really hear it in the boat since you're going 70 mph and the wind blows the noise away. He does say that people up and down the river hear him coming.